The Octave
Letter names on the keyboard repeat in a recurring pattern that goes from A to G. There are always eight white keys between a given letter name and its next occurrence up or down on the keyboard (counting the first and last keys, as illustrated in the table below). This distance of eight white keys is called an octave. This designation should be fairly easy to remember because it uses the prefix oct-, which means eight, just like in octopus and octagon.
| A | B | C | D | E | F | G | A |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| An octave from A to A | |||||||
Keys on the keyboard that are separated by an octave have the same letter name because they sound quite similar to each other, even though one pitch is clearly higher or lower than the other (such as the three Cs in the example below).
Octave Designations
How can we distinguish between two pitches that have the same letter name, but that occur in different octaves, such as the three Cs on the keyboard above?
Unfortunately, there is no one standard system in place today that musicians use to designate octaves. In fact, there are several ways of labeling pitches according to their octave position. Different systems of octave designation provide a method for identifying musical notes from the lowest to the highest pitch. In this course, we will use the octave designation system of the Acoustical Society of America, which labels the pitches with a capital letter, followed by a number that represents the octave in which they appear. In the example above, the first C on the keyboard is labeled C3, so the one an octave above it is labeled C4, and the one above that is C5. These three Cs are in three different octave registers.
Octave Registers
Octave registers run from C to C, starting with C1 in the lowest register of the keyboard and ending with C8—the last C on the keyboard. Pitches that fall within the octave from C to C belong to that octave register. For example, all of the pitches following C3 (i.e., between C3 and C4) are labeled with octave register 3: C3, D3, E3, F3, G3, A3, and B3. The octave register after C3 is labeled C4. All of the pitches following C4 (i.e., between C4 and C5) are labeled with octave register 4: C4, D4, E4, F4, G4, A4, and B4.
The following example shows the octave designations for the pitches C and F. One particularly important pitch here is C4, which musicians refer to as middle C, since it is located roughly in the middle of the keyboard.
Octave nomenclature and register of C and F
In an 88-note keyboard, the four notes before C1 correspond to the notes A, A♯/B♭, and B. These are labeled A0, A♯/B♭0, and B0.
Remember
- Octave registers begin and end with the pitch C
- Middle C is C4
The Staff and the Keyboard
The pitches that we have been discussing in terms of the keyboard may also be notated on a musical staff, a system of notation that will be the next major topic of study in this course. The interactive exercise below shows the relationship between letter names, notes on the staff, and the keyboard from C2 to C6. Feel free to explore and whet your appetite for the next section of our course!
The Staff and the Keyboard
In the graded quiz that follows, you will need to be able to identify all of the notes (white keys and black keys) on the keyboard. Remember that keys on the keyboard can have more than one name! You may also be asked to identify whole and half steps on the keyboard.
Core Skill
- Locate all Cs and their octave registers on the keyboard quickly and accurately.
- Locate letter names, e.g., F, B, on the keyboard quickly and accurately.
- Locate letter names with octave register, e.g., F3, B5, on the keyboard quickly and accurately.